Very high energy gamma rays from the direction of Sagittarius A*
We report the detection of a point-like source of very high energy (VHE) gamma-rays coincident within 1′ of Sgr A*, obtained with the H.E.S.S. array of Cherenkov telescopes. The gamma-rays exhibit a power-law energy…
The status of the H.E.S.S. project
The High Energy Stereoscopic System (H.E.S.S.) – is a system of four, 107 m^2 mirror area, imaging Cherenkov telescopes under construction in the Khomas Highland of Namibia (1800 m asl). The H.E.S.S. system is…
The optical system of the H.E.S.S. imaging atmospheric Cherenkov telescopes, Part I: layout and components of the system
H.E.S.S. — the High Energy Stereoscopic System — is a new system of large imaging atmospheric Cherenkov telescopes, with about 100 m^2 mirror area for each of four telescopes, and photomultiplier cameras with a…
The optical system of the H.E.S.S. imaging atmospheric Cherenkov telescopes, Part II: mirror alignment and point spread function
Mirror facets of the H.E.S.S. imaging atmospheric Cherenkov telescopes are aligned using stars imaged onto the closed lid of the PMT camera, viewed by a CCD camera. The alignment procedure works reliably and includes…
Limits on an energy dependence of the speed of light from a flare of the active galaxy PKS 2155-304
In the past few decades, several models have predicted an energy-dependence of the speed of light in the context of quantum gravity. For cosmological sources such as active galaxies, this minuscule effect can add…
On design studies for future 50 GeV arrays of imaging air Cherenkov telescopes
Arrays of imaging air Cherenkov telescopes (IACTs) like VERITAS, HESS have been recently proposed as the instruments of the next generation for ground based very high energy gamma-ray astronomy invading into 50-100 GeV energy…
